We propose a randomized control trial to test an intervention sponsored by three professional associations to improve the adoption, maintenance, quality and diffusion of cancer early detection activities in rural primary care practices in North Carolina. Sixty-eight randomly chosen primary care practices in two geographic areas of North Carolina will be grouped into similar pairs and randomly assigned to intervention and control groups. The intervention group will receive an intensive "Office System for Preventative Care" (OSPC) program of academic detailing, meetings with physicians and staff, consultation about office systems and educational modules about proper technique of early detection activities. The effect of the OSPC program will be measured by the proportion of eligible patients receiving early detection activities for four cancers before and after the stage of adoption by participating practices. The project will include a phase to diffuse the intervention to practices beyond the study group.